Three equal masses m are placed at the three corners of an equilateral triangle of side α. Find the force exerted by the system on another particle of mass m placed at

(a) The mid-point of a side,


(b) At the Centre of the triangle.


(a)From the figure, the forces exerted by particles O and Q are equal and opposite. Hence, only particle P is exerting a force on A.


Distance between particle P and A is


Therefore, the force is given by


(b) At the midpoint (B), the gravitational forces from the particles are equally balanced in all directions. Hence, the total force is zero.


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